A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-energy exhaust gas flow. The high-energy exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
Additional engine efficiencies are realized with variable turbine vanes that provide for variation in the flow of gas flow to improve fuel efficiency during operation. Gaps between the root and tip of such variable vanes may allow some gas flow around an airfoil and therefore reduce efficiency gains. Moreover, gas flow within the turbine section is at elevated temperatures and therefore gas flow over a tip or root portion can increase airfoil temperatures.
Turbine engine manufacturers continue to seek further improvements to engine performance including improvements to thermal, transfer and propulsive efficiencies.